In the 1970s, when I first learned to program, I was just as likely to receive advice from a woman as from a man. Those advisors included someone with a severe visual impairment and the first openly gay person I had encountered.

In the 1980s, I was working in IT at least a quarter my colleagues in technical roles were female. Staff at managerial levels were overwhelmingly male, but that's another story.

Now when I visit IT companies or meet with their representatives, technical roles seem more strongly gendered than ever. When I am invited to interview people about technology, they are far more likely to be male than female.

On my occasional shop floor visits I typically see a roughly similar number of men and women at work, but the developers, architects and so on tend to be male. They're not all of European heritage, but I can't remember the last time I encountered a person with disability in this part of the workforce.

It may seem presumptuous for an older white male to comment on diversity, but last year the Australian Human Rights Commission reported that “over a quarter of Australians aged 50 years and over report that they had experienced some form of age discrimination in the last two years”.

“When managers were asked if they factored age into their decision making, a third responded that they did,” the report found.

And here's the overlap: "Of those who did not participate in the workforce in the last two years but would have liked to, one in five reported that it was because their skills were not current."

The nature of IT is that specific technical skills date very quickly. It is enough of a challenge to keep refreshing those skills while you are working, but if you take say two or three years' parental leave it becomes a real struggle. Even if you can find the time for side projects or the money for training, employers (or perhaps recruitment firms) seem to strongly prefer candidates that are currently doing the job.

What changed during the last few decades is that more women want or need to return to work more quickly after having children. That's likely to be partly a matter of money – think about house prices – but also to maintain career continuity. If you don't go straight back to your old job it becomes a lot harder to find another position.

With these factors in mind, would it be a surprise that young women are choosing careers that are more forgiving in this regard?

So how many more women would be working in IT if policies were adjusted to encourage the retraining and rehiring of people with recent gaps in their resumes?

Mothers would be the main beneficiaries, but such measures would also make it easier for fathers to take parental leave, and assist those who are retrenched and do not immediately find a new job.